High-power double burner for gas cookers, with multiple concentric flame crowns

ABSTRACT

The present invention refers to a double burner for gas cookers with multiple concentric flames, characterized by high power and compact height, which comprises five Venturi mixing chambers, i.e. one central chamber ( 5   a ) with vertical axis that feeds the central burner and four regularly spaced chambers ( 6   a ) with inclined axis that feed the external annular burner.

The present patent application for industrial invention refers to a double burner for gas cookers, with multiple concentric flame crowns, characterised by high power and compact height.

The term “double burner” indicates a burner comprising two different gas inlet conduits, provided with corresponding taps, which separately supply two or more concentric flame crowns, which can be selectively turned on or off, being autonomously supplied by two channels derived from the said separate pair of inlet conduits.

Although provided with multiple concentric flame crowns, traditional burners are characterised in that they only have one gas inlet conduit, with corresponding tap, which supplies all channels used to bring the air-gas mixture to the burner head.

This means that in traditional burners concentric flame crowns are always on or off simultaneously, while in the case of a double burner the user can decide to turn on all or some of the flames crowns.

In view of the above, the purpose of the present invention is to provide a double burner for gas cookers, with multiple concentric flame crowns, of known type, which is characterised by unprecedented power.

It must be reminded that models of double burners with multiple concentric flame crowns of known type are characterised in that they use a Venturi-effect mixing chamber (technically known as “Venturi”) with vertical axis for the central burner, while the mixing chamber of the external burner with annular shape is obtained with two Venturi with vertical axis or with one Venturi with horizontal axis.

Since the central burner has limited power due to its position, the external burner has the highest power, which is entrusted to the Venturi chambers of the external burner.

As it is known, the power supported by the Venturi chamber depends on the diameter of its contracted section, or groove, which in turns affects the length of the Venturi diverging section, meaning that the groove section and the length of the Venturi diverging section must be increased to increase power. In view of the above, in traditional models of double burners with multiple concentric flame crowns it is not possible to obtain high power on the external burner, since the limited height of the burner prevents from extending the length of the Venturi chambers with vertical axis of the external burner.

For the aforementioned reasons, double burners with multiple concentric flame crowns of known type are currently operated at the end of their power. This condition corresponds to high combustion values (values close to maximum limit set by CEN 30.1 European Norm and out of the range set by Chinese regulations).

The burner of the invention has been devised to overcome this typical functional limit of traditional burners. The burner of the invention is provided with a central burner traditionally associated with a Venturi chamber with vertical axis and with a totally innovative external burner associated with more than two, preferably four, Venturi chambers with inclined axis and radial direction, each of them having a unitary power according to the burner dimensions.

For example, in a burner with two Venturi chambers, in order to obtain 4 kW, each single Venturi chamber must be loaded at 2 kW; in the case of a burner with four Venturi chambers, reducing the load of each Venturi chamber to 1.25 kW, minus 62.5%, a maximum power of 5 kW is obtained, with consequent reduction of combustion values generated when the external burner delivers the maximum power.

The burner of the present invention traditionally comprises a tub-shaped body, whose bottom wall is traditionally provided with two different, non-communicating conduits with horizontal axis for gas inlet, each of them being designed to selectively supply the aforementioned channels.

Both gas inlet conduits reach the centre of the body at a slightly different height, in such a way that, if necessary, they can communicate by means of a hole with vertical axis that ends in the lower conduit from the upper one.

A vertical channel branches upwards from the upper inlet conduit, on which the first gas nozzle designed to introduce gas in the mixing chamber that supplies central flame crowns is mounted. According to the present invention, more than two ascending and diverging channels branch from the lower inlet conduit, on which corresponding nozzles designed to introduce gas in the mixing chamber that supplies the external flame crowns are mounted.

A shaped chamber with Venturi effect is housed downstream each gas nozzle, which favour mixing of gas with primary air extracted in the upper part of the cooktop.

This means that the burner of the present invention is provided with minimum four mixing Venturi chambers, one central chamber with vertical axis above the first nozzle and minimum three regularly spaced three chambers with inclined axis, respectively supplied by different nozzles.

These chambers are situated inside the burner head, that is to say in the circular “dish” contained in all models of burners, which is characterised in that it is provided with a concentric series of multiple toothed crowns, on which the burner caps are placed to close the cavities of the toothed crowns, it being known that a flame originates from each cavity.

More precisely, the head is formed of a lower dish and an upper dish, shaped in such a way that they can perfectly match in order to form the mixing chambers with inclined axis, while the mixing chamber with vertical axis is entirely situated in the centre of the upper dish, which is the dish with the concentric series of multiple toothed crowns.

The lower dish is provided with a lower series of radial partitions that determine self-centring and detachment from the nozzle-holder body. Detachment is indispensable to guarantee sufficient introduction of primary air extracted from above the cooktop.

For major clarity the description of the double burner of the invention continues with reference to the enclosed drawings, which are intended for purpose of illustration only and not in a limiting sense, which illustrate a double burner with multiple flame crowns provided with four Venturi chambers with inclined axis designed to supply the external flame crowns.

FIG. 1 is a cross-section of the burner of the invention with a diametrical vertical plane passing through the axis of the gas inlet conduit designed to supply external flame crowns.

FIG. 2 is a cross-section of the burner of the invention with a diametrical vertical plane passing through the axis of the other gas inlet conduit, which is positioned at a higher height than the first conduit.

FIG. 3 is a plan top view of the body of the burner according to the present invention.

FIG. 4 is a plan top view of the head of the burner according to the present invention without caps.

With reference to the aforementioned figures, the double burner of the invention comprises a circular tub-shaped body (1) which houses a raised central cross-piece (2) with housings for multiple gas nozzles.

The body (1) traditionally houses two different, non-communicating gas inlet conduits (3 and 4), each of them selectively and respectively supplying the nozzle associated with the central flame crown and the group of nozzles associated with the external flame crowns.

Both gas inlet conduits (3 and 4) reach the centre of the body (1) at slightly different heights; more precisely, the upper inlet conduit (3) exactly ends in the centre of the body (1), while the lower inlet conduit (4) goes beyond the centre, as shown in FIG. 1.

A vertical channel (3 a) branches upwards from the upper inlet conduit (3), on which the first gas nozzle (5) designed to introduce gas in the Venturi mixing chamber that supplies central flame crown (FC) is mounted; while four ascending and diverging channels (4 a) branch from the lower inlet conduit (4), on which corresponding nozzles (6) designed to introduce gas in the mixing chambers that supplies the external flame crowns (FE) are mounted. A Venturi mixing chamber (5 a) with vertical axis is situated downstream the nozzle (5), while four Venturi mixing chambers (6 a) with inclined axis, preferably from 40° to 60°, are situated downstream the four nozzles (6). Moreover, the burner of the invention comprises a head (T) formed of a lower dish (7) and an upper dish (8) shaped in such a way that they perfectly match.

More precisely, the lower dish (7) has a truncated-conical profile and has a stepped external border (7 a) that supports and centres the upper dish (8) with a stepped perimeter collar (8 a).

The upper dish (8) is also supported and centres in the central flange (9) of the lower dish (7).

The two dishes (7 and 8) respectively have semi-conduits (7 b and 8 b) that form the Venturi mixing chambers (6 a); downstream the chambers a deflector partition (10) shaped as a V, is situated on the lower dish (7), which favours bifurcation of the air-gas mixture flow coming from the chambers (6 a), conveying it inside the corridor (11) that supplies the external concentric flame crowns (FE), as shown in FIG. 4, which clearly shows the three toothed crowns (12) above the upper dish (8).

The annular corridor (11) is formed of four identical consecutive and communicating corridor sections, each of them being bordered by a pair of deflector partitions (10).

The corridor (11) is closed by an annular cap (13), on whose internal and external border the aforementioned external concentric flame crowns (FE) are formed.

The Venturi mixing chamber (5) is completely housed in the upper dish (8) and ends in a circular compartment laterally closed by the toothed crown (12) with lower diameter and superiorly by a circular cap (14), on whose external border the central concentric flame crown (FC) is formed.

With special reference to FIG. 1, the lower dish (7) is provided with a lower series of radial partitions (15) that determine self-centring and detachment from the nozzle-holder body (1), thus guaranteeing sufficient introduction of primary air (A) extracted from above the cooktop (P).

In order to convert the double burner of the invention into a traditional burner with three concentric flame crowns, a hole with vertical axis is drilled in central position on the body (1), starting from the lower gas inlet conduit (4) and ending in the coaxial vertical channel (3 a) where the nozzle (5) is engaged.

In this way, only the lower conduit (4) needs to be connected to the gas supply network in order to simultaneously supply all nozzles, the central one (5) and the lateral ones (6), it being evident that in this case the upper gas inlet conduit (3) needs to be closed to prevent the gas introduced in the lower conduit (4) from exiting the burner body and go up the upper conduit (3).

To avoid using another element in addition to the body (1) of the burner, such as a closing cap for the conduit (3), the length of the conduit (3) needs to be suitably reduced.

Since the body (1) is obtained with die-casting process, the reduction in length can be easily and cost-efficiently obtained by simply moving back the pin used inside the mould as “core” of the upper conduit (3). 

1. Double burner for gas cookers, with multiple concentric flame crowns, of the type comprising a head (T) with multiple concentric flame crowns and a circular tub-shaped body (1) which houses a nozzle-holding cross-piece (2) and two separate, non-communicating gas inlet conduits (3 and 4), each of them being designed to selectively and respectively supply the nozzle (5) associated with the central flame crown (FC) and the group of nozzles (6) associated with external flame crowns (FE); burner characterized in that the group of nozzles (6) is formed by minimum three regularly spaced nozzles (6) that supply corresponding Venturi mixing chambers (6 a) with inclined axis, while the nozzle (5) supplies a corresponding Venturi mixing chamber (5 a) with vertical axis whose diverging section ends in a circular compartment laterally closed by a toothed crown (12) of the central flames (FC) and superiorly by a circular cap (14); it being provided that the head (T) is provided with a lower series of radial partitions (15) that determine self-centering with respect to the nozzle-holder body (1), guaranteeing sufficient introduction of primary air (A) extracted from above the cooktop (P).
 2. Burner as defined in claim 1, characterized in that both gas inlet conduits (3 and 4) reach the centre of the body at slightly different heights.
 3. Burner as defined in claim 2, characterized in that the upper inlet conduit (3) exactly ends in the centre of the body (1), while the lower inlet conduit (4) goes beyond the centre.
 4. Burner according to claim 2, characterized in that a vertical channel (3 a) branches upwards from the upper inlet conduit (3), on which the nozzle (5) is mounted, while a series of minimum three regularly spaced ascending and diverging channels (4 a) branch from the lower inlet conduit (4), on which corresponding nozzles (6) are mounted.
 5. Burner as defined in claim 1, characterized in that the head (T) is formed of a lower dish (7) and an upper dish (8), shaped in such a way that they can perfectly match, where the lower dish (7) has a truncated-conical profile and has a stepped external border (7 a) that supports and centres the upper dish (8) with a stepped perimeter collar (8 a), which is also supported and centred in a central flange (9) on the lower dish (7).
 6. Burner as defined in claim 5, characterized in that the lower dish (7) and the upper dish (8) respectively have semi-conduits (7 b and 8 b) that form the Venturi mixing chambers (6 a), while the chamber (5 a) is completely housed in the upper dish (8).
 7. Burner as defined in claim 5, characterized in that it comprises, downstream the chambers (6 a), a deflector partition (10) shaped as “V”, situated on the lower dish (7), which favours bifurcation of the air-gas mixture flow coming from the chambers (6 a) conveying it inside a corridor (11) that supplies the external concentric flame crowns (FE).
 8. Burner as defined in claim 7, characterized in that the head (T) comprises an annular cap (13) and a circular cap (14) that respectively close the corridor (11) and the Venturi chamber (5); it being provided that the disk (B) has three toothed crowns (12).
 9. Burner as defined in claim 5, characterized in that the partitions (15) are obtained from the same piece as the lower dish (7).
 10. Burner as defined in claim 4, characterized in that a hole with vertical axis is drilled in central position on the body (1), starting from the lower gas inlet conduit (4) and ending in the coaxial vertical channel (3 a) where the nozzle (5) is engaged and characterized in that, in the presence of the hole with vertical axis, the upper conduit (3) is occluded. 